Means for vibrating screens and the like



Filed June 50, 1937 4 Sheets-Sheet 1 June 20, 1939. J. w. SHERWEN MEANSFOR VIBRAIING SCREENS AND THE LIKE Filed June 50, 1957 4 Sheets-Sheet 2Fig. 2.

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June l939- J. w. SHERWEN 2,163,249

IEANS FOR VIBRATING SCREENS AND THE LIKE Filed June 59, 1937 4Sheets-Sheet 3 Fig. 3.

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June 20, 1939. w SHERWEN 2,163,249

IEANS FOR VIBRATING SCREENS AND THE LIKE Filed June 30, 1937 4Sheets-Sheet 4 Patented June 20, 1939 UNITED STATES PATENT, OFFICEJoseph William Sherwen, Erlth, Kent, England, assignmto The GeneralElectric Company, Limited, London, England Application June 30, 1937,Serial No. 151,088

Iii Great Britain July '1, 1936 'IClaims.

This invention relates to driving means for concentrating, sifting,conveying, moulding, pulverising, crushing and similar apparatus,comprising a table, screen, tray or the like adapted to be vibrated byvibrating means such as' the armature of electromagnetic means suppliedwith intermittent current.

It has been usual hitherto to connect the said vibrating means to thetable, screen, tray or the like by rigid means such as bolts, and it hasbeen found that on accountof the intense vibration and the slightbending at each stroke, these bolt means will break even if they aremade of an expensive steel.

The object of the invention is to provide an improved drivingarrangement which does not necessitate the provision of such rigid boltmeans.

According to the invention driving means for concentrating, sifting,conveying, moulding, pulverising, crushing or similar apparatuscomprising a table, screen, tray or the like adapted to be vibrated byvibrating means, such as the armature of electromagnetic means suppliedwith intermittent current, comprises resilient means associated withsaid vibrating means and adapted to be connected to said table or thelike whereby the vibrations of the driving means may be imparted to thesaid table or the like through a resilient connection. The saidresilient means may comprise coiled springs and/or leaf springs.Preferably adjustable constraining means are provided for said resilientmeans wherewith the natural frequency of vibration of the vibratingmeans may be adjusted. It is found to be pref- 35 erable that thisfrequency should accord with the frequency of energization of the saidvibrating means.

The invention will now be particularly described with reference to theaccompanying drawings which show examples of construction.

Figure 1 of the drawings shows a plan view of one form of driving means;Figure 2 a section on the line AA in Figure 1; and Figure 3 a section onthe line BB in Figure 2. Figure 4 shows a side elevation of a vibratingfeeder with a driving means, as shown in Figures 1, 2 and 3, amxed tothe feeder. Figure 5 shows a part side elevation corresponding to thatin Figure 4 but with a modified form of driving means. Figure 6 showsyet a further modification which may be made to the driving means shownin Figures 1, 2 and 3. Figure 7 shows a perspective view of anothermodified form of driving means.

Referring to Figures 1, 2 and 3, the driving means comprises a metalcasting 1, formed with symmetrical upstanding shoulder portions 2, thespace between the shoulder portions being occupied by a U shapedlaminated core 3, the limbs of which carry coils I. The core 3 issecured to a supporting surface 5 of the casting by bolts 6. 5 Coverplates 1 and 8 are provided for the coils l.

Curved faces 9 and III are provided at the back and front of the castingand to the lower end of these faces respectively are clamped the loweredge portions of resilient plates ll and 12. The 10 plate ll carries atits top edge portion clamping plates 13 and It for a laminated armature15.

Four coiled springs [6 are arranged between the shoulder portions 2 andthe plates II and II respectively; each of the two bolts l'l extends 16through the two plates H and I2, through two of the coiled springs andthrough a hole IS in the associated shoulder portion. The bolts areprovided with a head at one end and an adjustable locked nut I9 at theother. By adjusting the nut 20 I! on each bolt the compression of thesprings I6 and the free length of plates H and I2 from the curved faces9 and It can be adjusted; and therefore the natural frequency ofvibration of the armature and plates II and I! can be regu- 25 lated.

Eyebolts 20 are provided at the ends of the casting by which theapparatus may be suspended. These eyebolts are preferably situated at ornear the axis which is found in practice to rotate 30 rather than tovibrate. The position of this axis is related in some way, thoughcomplex, on account of the complex nature of the driving force, with thecentre of percussion of the apparatus. The approximate position of thesaid axis may be located easily by experiment. The points at which theeye bolts are fixed will be referred to hereinafter as dead points.

One method of attachment of the driving means is shown in Figure 4. Herean angle plate 21 is rigidly attached to the plate 12 by means of thebolts l1, and to the feeder -22 by some form of securing means (notshown) or by welding.

The whole combination is suspended by four rods 23 (of which two onlyare shown) one pair being attached to the eyebolts 20 in the casting Iand the other pair being attached to eyebolts 24 afllxed to an anglecross-piece 25 welded or otherwise fixed to the base of the feeder.Shock absorbers may be provided in the rods in known manner; but bypositioning the supporting bolts in the manner above described, there isno real need for shock absorbers.

, On account of the choice of the dead points for the points ofsuspension the vibration is trans- 55 mitted as by a lever, acting aboutthe axis passing through these points.

It will be seen that in the arrangement shown in Figure 4, the armatureI5 is coupled to the feeder through the springs I8 and that the motionof the armature is transmitted to the feeder wholly through thesesprings, so that the bolts I! will not be subject to fatigue duringvibration. If desired one or more additional driving means may beconnected to the feeder.

In the arrangement shown in Figure 5, the plate I I is replaced by alarger plate 26 the upper end of which is secured to an angle plate 21,this plate 21 being fixed to the base of the feeder .through anadjustable fixture; this fixture may suitably comprise fixing bolts 28extending through slots in the base of the feeder. Here the connectionof the armature 5 to the feeder is through the resilient plate, andagain the bolts I! are not subject to the strains hereinbefore referredto when the feeder is being vibrated. In

this arrangement, if the fixing for the angle plate 21 is sumcientlyadjustable, the bolts I! may be removed after fixing.

Referring to Figure 6, the arrangement of further coiled springs 29between the plates 26 and I2 and the ends of the bolts l1. Tuning of thefrequency of vibration may be effected, as before, by adjusting thedegree of compression of the springs l6 and 29.

Referring now to Figure '7, a casting 30 is formed, in a similar mannerto the casting I,

with shoulder portions 3| against which coiled,

springs 32 abut. Here however, shoulder portions extend on either sideof the casting and eight coiled springs with compression bolts 33 areprovided. The casting 30 carries an electromagnetic core (not visiblebut similar to core 3) which is adapted to be energised to attract thearmature 34. The armature is clamped between angle brackets 35 to whichare secured resilient curved plates 36. The other end of each plate 36is secured to a base member 31 carrying the casting 30;

The base member 31 is adapted to be secured to a table, screen, mould orthe like adapted to be vibrated, and intermittent energisation of thecoils on the core results in attraction and release of the armature andthe reaction on the springs 32 causes the base 31 to vibrate. Here thearmature is connected to the table or the like through the resilientplates and coiled springs. If the coils are compressed to a suitableextent by the bolts 33, the vibrating system can be tuned to vibratewith a frequency resonant with that of the supply to the energisingcoils.

Suitable arrangements for energising the coils of the electromagnets aredescribed in British Patent Specifications Nos. 421,657 and 441,733.

I claim:

1. Means for vibrating screens and the like comprising a member to bevibrated, a body portion, connecting means between said member and thebody portion for supporting said member for vibration, an electromagnetfixedly mounted on said body portion and arranged to cooperate with anarmature. resiliently supported by the body portion for vibrationrelative to the magnet when the latter is intermittently energized,means for supporting said body portion for oscillatory movement about arelatively fixed axis when said magnet is intermittently energized forvibrating the armature, and coil springs interposed between saidarmature and the body portion and between said body portion and theconnecting means for transmitting vibrations to said member to bevibrated.

2. Means for vibrating screens and the like, as in claim 1 wherein meansis provided for adjusting the compression of said coil springs so thatthe natural period of vibration of the armature will conform to theintermittent energization of the magnet.

3. Means forvibrating screens and the like as in claim 1- wherein saidbody portion is supported for oscillatory movement by depending linkspivotally connected to the body portion at opposite ends of said axis ofoscillation.

4. Means for vibrating screens and the like comprising a member to bevibrated, a body portion, resilient connections between the body portionand said member for supporting the latter for vibration, anelectromagnetfixedly mounted on said body portion, an armature arrangedto cooperate with said magnet, resilient connections between saidarmature and the body portion for facilitating relative vibrations ofthe armature and magnet, shoulder lugs on said body portion adjacentsaid magnet, compression coil springs between said shoulder lugs andeach of said resilient connections for transmitting relative vibrationsof the armature and magnet to said member to be vibrated, means foradjusting the compression of said springs so that the. natural period ofrelative vibration of the armature and magnet may conform withintermittent energizatlon of the magnet, and means for supporting saidbody portion for oscillation about an axis coinciding-substantially withthe center of oscillation of said body portion when relative vibrationsof the armature and magnet are effected by the intermittent energizationof the magnet.

5. Means for vibrating screens and the like as in claim 4 wherein saidresilient connections between the armature and said body portioncomprises a leaf-spring-like resilient plate extending beyond thearmature and connected with said member to be vibrated.

6. Means for vibrating screens and the like as in claim 4 wherein oneend of said member to be vibrated is supported by the body portionthrough said resilient connection andthe other end of said member issupported by depending links pivotally connected with said member.

7. Means for vibrating screens and the like as in claim 4 wherein saidmeans for adjusting the compression of said springs comprises boltsextending through said resilient connections and provided with lock nutsfor holding the adjustment.

JOSEPH WILLIAM SHERWEN.

